First edition. "... Dutch pioneer in microscopy, the first to see and describe Bacteria, Red Blood Corpuscles, Spermatozoa" (Horblit 65). A complete set of the second series of Leeuwenhoek's famous letters ("Send-brieven", numbered I-XLVI) to the Royal Society of London which is the last volume of his collected work. The attractive frontispiece by J. Goeree shows the portrait of Leeuwenhoek hold by an angel.